Brake mechanism for railway cars



c. L. MooRMAN l v BRAKE MECHANISM FOR RAILWAY GARS ,Filed Jan. '29.311936 2 sheets-Smm 1.- A

2 Sheets-Sheet 2 ||I il IIIIT llll II. HIIHII 1 C. L. MOORMAN BRAKEMECHANISM FOR RAILWAY CARS Filed Jan. 29. 1926 Aug.- 16, 1927.

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. Patented Aug. 16, 1927.

narra oHAaLEs L. MooRniAN,

STATES or CHICAGO, ILLINOIS.

BRAKE MECHANISM FOR RAILWAY CARS.

Application led January 29, 1926. Serial No. 84,538. i

The present invention relates to brake mechanism for railway cars.

In the ordinary brake system employed on railway cars, there is alwaysconsiderable slack in the various linked connections, and in the spacingof the brake shoes from the wheels, which, in the operation of the handbrake must be taken up by several rotations ofV the brake staff beforethe brakes can bei0 come effective. It is desirable to take up thisslack with a relativelyv rapid motion to permit quick setting of thebrakes, but at the same time it is practically imperative that the nalsetting of the'brakesbe through a mechanical advantage which will applythe necessary braking effort to the wheels.

lt has been proposed heretofore to use braking mechanism-'effective onthe hand brake portion ofthe system-which will give a changing ratio ofleverage for taking up the slack with a relatively rapid motion of lowmechanical advantage, and for actually pressing the brake shoes againstthe wheels with a slower motion of high mechanical advantage. Theseprior construc-l tions, however, have operated upon the theory ofchanging the leverage ratios with the degree of movement of theoperating parts, irrespective of when the Abrake shoes actually engagethe brake wheels. As a consequence, the brake shoes might Ibe engagingthe wheels When the system wasoperating under low mechanical advantage,or they might not engage the wheels until after the system had operatedthrough a considerable part of its slow motion high mechanical advantagetravel.

It is the `fundamental object of the present invention to improve onthese prior systems by providing brake mechanism which utilizes there-action pressure of the brake shoes engaging the wheels to eect theshifting of leverage ratios, rather than utilizing the distance throughwhich the operating1 parts' 'u have moved for determining the pointwhere the leverage ratios arechanged or shifted.

Itis a further object of the invention 'to provide brake mechanismwhich` willlelfect this shifting of leverage ratios .with a quick,decided motion as soon as the re-action I' pressure on the operatinparts indicates thatl the brake shoes are a l in rm contact with theirrespective wheels.

It is a further object of the invention to provide brake mechanism ofthisA general type in which the mechanism will bey positively locked inits high leverage ratio when the maximum braking effort is being appliedto the wheels.

Other objects and advantages of my inventioii will appear from thefollowing devend of a railway-car brake mechanism it .will be apparentthat it may be employed in. connection with the pneumatically operatingpart of the system with equal advantage; and it Will also be apparentthat the essential features and characteristics of the invention can beembodied in brake systems for automobiles and other vehicles.

In the drawings laccompanying this de'- tailed description:

Figure 1 is a bottom plan view of the leverage changing or brakeboosting mechanism.

Figure 2 is a side view thereof taken generally on the plane of the line2-2 of Figure l; and

Figure 3 is a plan view of the frame of a typical railway car to whichmy invention may be applied.

Referring first to Figure 3, the car frame is designated 6 in itsentirety, this car frame being of any conventional construction. Theframe is supported on the usual end trucks having wheels 8-8. A brakestaff 9 rises from one end of the car having suitable bearing supportadjacent its upper and lowerl ends and carrying the usual hand wheel atits upper end, through which the brake mechanism is actuated in themanual operation thereof. This brake s ta'i' may, in the brefaderaspects of the invention, be considered as the equivalent of any sourceof braking energy.

finding around this brake stati", Vor

around a drum thereon is a first tension member or chain 11, which inlieu of a chain, may consist of a cable, or a rod with a'section ofchain or cable on the end thereof for winding on the brake staff. Asecond tension member, represented by the chain l2, leads to` the systemof linkage which operates the` brake shoes. This system of brakeoperating linkage ma be of any construction and assembly, t earrangement shown in Figure 3 being typical. In this arrangement, theend of the second tension member or chain 12 connects to the end of thepiston rod 13 extending from the air brake cylinder 14. This piston rodin turn has pivotal connection with a floating lever 15, the oppositeend of which has pivotal connection to a link 16. This link has pivotalconnection to truck lever 17 which is ivoted intermediate its ends at 18the brake beams 19.- The other end of this truck lever has pivotalconnection through a linkor rod 21 with one end of the other truck lever17. This latter truck lever has like ivotal connection at 18 to theotherbrake eam 19. The opposite end of this second truck lever 1 is adaptedto have adjustable pivotal anchorage in a bracket 21 secured to the carframe. The ends of the brake beams 19-19 -carry brake shoes 23 which areadapted to, bear against the wheels 8. Braking motion is transmitted tothe brake shoes of the other truck through a rod 25 which forms theoating pivot for the lever 15. Tension appliedl to this rod actuates thebrakes for the other truck through the vlever 15 and a system of linkagesimilar to that just described.

The brake boosting or variable ratio mechanism constituting the subjectmatter of the present invention is designated 27 in its entirety, and isinterposed between the first tension member 11 which leads from thebrake stati' 9 and the second tension member 12 which leads to thesystem of brake linkage. This brake boosting mechanism is mounted on abase plate 28 which is suitably bolted to the underside of the car. Theprincipal elements of this device comprise a main swinging arm or lever29, a secondary lever 31 in the form of a bell crank pivotally mountedon the outer end of the aforesaid main lever, a locking slide 32movably, supported on the main lever, and stationary cam means 33 forcamming the slide 32 in along the main lever.

The irst tension member or operating chain 11 connects to a clevis 35having pivot eyes which engage on opposite sides of the short arm 31a ofthe bell crank lever^31, a pivot pin 36 extending through the eyes ofthe clevis and the end of the Abell crank lever.

through these pivot hubs and nounced cam slope on these innersur acesThe two arms of the main lever 29 merge into a common vpivot .hub 43which engages between the arms of a forked pivot bracket 44, a pivot pin45 passing through the arms of the pivot bracket and tlirough the pivothub 43. The pivot bracket 44 is suitably fixed to the mounting plate orbase 28 by fastening bolts 46. l

Referring again to the secondary or bell crank lever 31, the other arm31b thereof has pivotal connection at 47 with a clevis 48 which extendsinwardly between the arms of the main lever 29 and is linked to the endof the second operating chain or tension member 12. This operating chainpasses around a roller 49 and thence back out between the spaced arms29a-29b of the main lever 29.

The roller 49 is carried by the slide 32, which slide is mounted forreciprocal motion between the arms 29"*--29b of the main lever 29. Thisslide preferably comprises a U-shaped stirrup 51l lying betweenthespaced arms of the main lever and having an eye 52 at its upper end towhich the other end of the tension spring l42 is connected. The forkedends of'this stirrup member have apertures therein through which passesa pivot pin 53, the roller 49 being rotatably mounted on this pivot pinill) between the sidesy of the stirrup.- The ends j of this pivot pin`53 extend outwardly through slots 55 in the side arms 291-29b of themain lever, these slots serving to guide the motion of the slide in apath ex tending substantially longitudinally of the main lever 29.Rollers 56 are mounted on the projecting ends of this pin on the outersides of thearms 29B-29b,the pin having a shouldered end, and a cotterpin or other equivalent means to hold the rollers on this pin. Thefcammeans 33 y'comprises two cam bars 33 and 33b which are disposed on theupper and lower sides of the main lever 29, this mainlever havingswinging movement between these cam bars. The vrollers 56-56 bearagainst curved cam surfaces 57 delined along the inner edges of thesecam bars.

VAtt one end, these two cam bars are fixed to a stud 58 rising from thebase plate 28, the two, bars being .held in spaced relation on this'stud Ito permit the swinging movement of the main lever therebetween.The oppositeend of the imler or upper cam bar 33b is riveted orotherwise secured to the base plate 28 as indicated at 59. Thecorresponding end ofthe othercam bar 33a is supported'by'an arched brace61 whichv is riveted to one end of the bar and which is supported at itsother vend on thel pivot pin 45.

In the construction shown the cam surfaces 57 are curved on arcs lyingin eccentric relation to the pivot 45, (a-relatively ro- 57 beingcontemplated as an alternative construction) whereby as the main leveror arm 29 swings to the right as indicated by the arrow ai, the rollers56, and thereby the slide 32, will be csimmed inwardly along this mainlever toward the pivot 45. The tension of the spring 42 resists thisinward movement of the slide, and when the braking tension is taken oflIthe main lever,this tension spring by exerting a cam re-acting force onthe rollers 56-56 will swing the main lever 29 back to its normalposition. This normal vposition is defined by the stops 64 against whichthe main lever is normally held by These stops consist of small flangesturned inwardly from the ends of the cam bars 33a and 331 and adapted tobe engaged by the left hand edge of the main lever 29.

Where the two side arms 29a-29b of the main lever converge to the pivothub` 43, they define a 'il-shaped portion 66 which has locking webs orshoulders 67 forming a locking slot therebetween. This locking slot isadapted to effect ,locking engagement with the second chain 12 when themovement of the slide 32 forces this chain down toward .the pivot 45.This slot is just of sufficient width to receive one of the links lyingin the plane of the slot, the engagement of the next adjacent link withthe edges of this slot positively locking the chain to the lever.

In the operation of the device, the Winding of the first chain-l1 on thebrake staff' 9, will rock the bell crank lever 31 around its pivot'SS,which in turn will exert tension on the second chain l2 pulling the samearound' thelocking roller 49. It will be noted that the second arm 31hof this bell crank lever is longer than the first arm 31a whereby anincreased rate of movement is transmitted to the second chain 12, thisleverage 'ratio giving rapid movement for taking up 'slack but havingminimum mechanical advantage; The tension of the spring 42 is soproportioned that throughout the entire operation of taking up slackfrom the'braking system, the main lever 29 will be held in the positionillustrated in Figure l. In this posit-ion the locking roller 39 isremoved from proximity to the locking slot and the second chain has`free passage between the arms of the main lever.

As soon as all of the slack has been taken up and the several brakeshoes engage their' respective wheels, a. high re-action tension will beset up in the second chain 12, and also in the first chain 11. Thiswillovercome the tension of the spring 42, resulting in the main lever29 being drawn back in the direction 'of pull of the first chain ortension member 11. In this backward movement of the main lever, theslide 32 and locking roller 49 will be forced inwardly the tension ofthe spring 42 acting through the rollers 56.

toward the pivot 45 with a relatively rapid motion, thereby locking oneof thev links of the secondary chain in the locking slot and positivelylocking this chain to the main lever. Thereafter continued swingingmovement ofthe main lever will transmit a pull to the secondary chain 12through the comparative short radius arm extending from the pivot 45 tothe locking slot 67. Simultaneously therewith, the first chain 11 willhe exerting its pull onv the main lever through a radius arm extendingfrom the pivot 45 out to the pivot pin 36 ofthe bell crank lever.Obviously, this preponderating ratio of leverage will give atremendously increased mechanical advantageA over the leverage ratiospreviously existing while slack was being taken out of the system,

is unwound.

As previously remarked, some of the features o f my invention have widerapplication than to the specific use on the hand" brake portion of arailway car braking system, and I intend that certain of the followingclaims be so construed. Moreover, the invention is capable ofconsiderable modifiposition as the chain 11 cation and rearrangement ofparts without l departing from the essence thereof.

l. In brake mechanism for railway cars, the combination of brake shoesadapted to engage the car wheels, operating linkage for said brakeshoes. a brake stafi", a ,first tension member leading from said brakestaff, a second tension member leading to said operating linkage, a mainlever, a secondary vlever pivoted on said main lever, said tensionmembers being connected to said secondary lever for one ratio of motlontransmittmg` leverage between said tension meinbers, and meansresponsive to there-action pressure in one of said tension members forlocking one of said tension members to said main lever to establish adifferent ratio of motion transmitting leverage between said tensionmembers.

2. In brake mechanism for railway cars, the combination of brakescooperating with the car wheels, operating linkage for said brakes, ,abrake staff, a first tension member leading from said brake staff,a'second tension 'member extending to said operating linkage, a. mainlever, a second lever pivoted on said main lever, said tension membersbeing connected to said secondary lever, wherelll tending to said,operating link-a e,

f a second tension by said secondary lever transmits operating movement.between said tension members while the slack is being taken out of theoperating linkage, and means responsive to the re-action pressure ofsaid brakes engaging the wheels for locking one of said tension membersto said main lever to establish a di'erent ratio of motion transmittingleverage between said tension members.

3. In brake mechanism for railway cars, the combination of brake shoesadapted to engage the car wheels, operatin linkage ,for said brakeshoes, a brake sta a first tension member leading from said brake staff,member extending to said operating linkage, and brake boosting mechanismcomprising a main lever, lever pivoted on said main lever, said teni;sionv member being connected to said secondary lever whereby said latterlever trans- 'mits operating movement between said tension members whilethe slack is being taken out of said operating linkage, and springcontrolled locking mechanism responsive to the re-action pressureincident in the brake shoes engaging said wheels for locking one of saidtension members to said main lever to establish a different ratio ofmotion transglitting leverage between said tension memers.

4. In brake mechanism for railway cars, the combinatonof brakes adaptedto eect braking engagement with@ the car wheels, operating linkage forsaid brakes, a brake staff, a irst tension member leading from saidbrake stall, a second tension member exa main lever, a secondary leverpivote on said main. lever, said tension members being connected to saidsecondary lever Jfor one ratio of motion transmitting leverage betweenout of the said operating linkage,

said tension members while the slack is being taken out of vsaidoperating linkage, locking means associated with said main lever, andspring means overcome by the re-action pressure of said brakes engagingthe wheels for placing said tension member and said locking means linlocking engagement.

5. In brake mechanism for railway cars, the combination of brakesadapted to apply a braking retardation to the car wheels, op-v4 eratinglinkage for said b"akes, a brake staff, a first tension member leadingfrom said brake staff, a second tension member extending to saidoperating linkage, and brake boosting mechanism comprising. a mainlever. a secondary lever` pivoted on said main lever, saidtensionmembers being connected to said secondary lever for one ratio ofmotion transmitting leverage between said tension memberswhile the slackis being taken and spring controlled mechanism cooperating with saidmain lever whereby said main lever transmitsmotion between said tensionmembers a secondary said brakes begin to exert their braking retardationon said wheels.

6. In brake mechanism Jfor railway cars', the combination-of brakesadapted to exert braking retardation on the car wheels, operatingVlinkage for said brakes, a brake sta, a first tension member leadingfrom said brake staff, a second tension member extending to saidoperating linkage, a main lever, a secondary lever pivoted on said mainlever, -said tension member being connected to said secondary lever,said secondary lever transmitting by its pivotal movement one ratio ofleverage between 'said tension members and means for restraining pivotalmovement of said main lever until said brakes begin to apply brakingretardation tov said wheels, said main lever thereafter transmitting byits pivotal movement a different ratio o leverage between said tensionmembers,

7 In brake mechanism for railway cars, the combination ofbrake shoesadapted to engage the car wheels, operating` linkage for said brakeshoes, a brake staff, a rst tension member leading from said brake staE,a

second tension member extending to said I operating linkage, and brakeboosting mechanism comprising a main lever, a secondary lever pivoted onsaid main .lever, said tension members being connected to said secondarylever and one ratio of motion transmitting leverage between said tensionmembers, spring means normally tending to hold said main lever againstpivotal movement, and means for locking one of said tension members tosaid main lever when there-action pressure in the braking systemovercomes said spring means.

8. The combination with brake mechanism for railwaycars, having brakeshoes operating linkage therefor and a brake staff, of brake boostingvmechanism comprising a main lever', a second lever pivotally supportedon said main lever, the ends of said secondary lever being connected totension members extending to said brake stai land its said operatinglinkage, vs'aid secondary lever by its pivotal movement on said mainlevertransmitting one ratio of-leverage between said tension members,and means responsive to the re-action pressure in the braking system forlocking one of said tension members to said main lever 'whereby pivotalmovement of said main lever transmits a diferent ratio of motiontransmitting leverage between said tension members.

9. In brake actuating mechanism of the class described, the combinationof -a main lever, a secondary lever pivotally supported on said mainlever, the ends of said secondary lever being adapted to connect to thetension members of the brake system, said secondary lever transmittingoperating movement between said tension members while ed to have itsends connected to tension members leading to the bra-ke staff, and tothe operating linkage, spring means normally -tending to hold said mainlever against pivotal movement, and means for positively locking saidmain lever to one of the tension members when the re-action pressure ofthe brakes overcome said spring means.

11. In brake mechanism of the class described, the combination of a mainlever s comprising two'- spaced arms, a bell crank lever pi'votedbetween the outer ends ofsaid arms, said bell crank lever being adaptedto have its ends connected tothe tension mem- Y bers leading to thebrake stall' and to the operating linkage, a slide movably supportedbetween the arms of said mam lever, a

` locking roller carried by said slide around which passes the tensionmember leading to the operating linkage, al stationary cam surface, acam roller cooperating therewith carried b said slide, spring meansconnected tosai slide and by its pressure transmitted through said camroller to said cam surface normally tending to hold'said main leveragainst pivotal movement, and a locking shoulder on said main leveradapted to effect locking engagement with the tension member extendingto the operating linkage when lsaid main lever 'is moved pivotally.

12. In brake mechanism of the class described, the combination of a mainlever com rising a pair of spaced arms, a bell cran lever pivotallysupported between the outer ends of said arm, one end 'of-said bellcrank lever being adapted to be connected to a\,first chain leading tothe brake staif, the other endof said bell crank lever being adaptedtobe connected to a second chain leading to the operating linkage, aslide reciprocably mounted between the arms of said main lever, a rollercarried by said slide and around which said second chain is adapted topass, a cam element and a roller element cooperating therewith, one ofsaid elements having fixed mounting relative to said main lever and theother of said elements being carried by said slide, a. spring connectedto said slide and operative-through the, re-action pressure exertedbetween said elements to normally hold said main lever against pivotalmovement, and a locking recess into which said second chain "is adaptedto be forced upon the reaction pressure 'of the brake mechanismovercoming said spring.

In witness whereof, I hereunto subscribe my name this-11th day ofJanuary, 1926.

CHARLES L. MOORMAN.

